The invention is directed to a method for flow control of data, by which users can exchange data via nodes connecting an origin to a destination in a network in which the nodes are connected to one another via arbitrarily meshed lines, and every node is equipped with a transmission memory means and with a reception memory means.
The flow control of data within meshed data networks serves the purpose of carrying out the transmission of data throughout the network without information losses. When there are a number of simultaneously users of the network, having different data transmission quantities, within the same period of time, a data jam can occur, which can lead to considerable disturbances in the network and potentially to total data loss. "European Computer Manufacturers Association" (ECMA/TC24/84/223, Supercedes 84/188), a European standard for computer users, discloses what is referred to as an "end-to-end flow control" method, wherein the memory means at the destination and origin nodes of a data connection are monitored to determine their data acceptance capability. In case a defined memory capacity is exceeded, then an inhibit bit is generated and returned from the transmission memory means at the destination node to the reception memory means at the originating mode. At the latter, this information effects the inhibition of the transmission, so that it is assured that data stored in the transmission memory means are no longer transmitted. However, as soon as the reception memory means is again capable of accepting further data, when the data jam in the originating node has been corrected, the transmission of further data from the destination node to the originating node is re-initiated with the transmission of a corresponding enable bit from the destination mode and the reception thereof at the originating node.
This monitoring of the data memories at the respective destination and originating nodes assures that the data transmission between these two nodes is protected, but it leaves the remaining transmission path out of consideration. However, since the greatest variety of users transmit their data with different data transmission rates, via a great variety of devices such as data terminals, computers, etc., particularly in extensive intermeshed data networks, there is a need for an expansion of the method known from the European standard.